Patrol helicopter usually spawn after the Chinook does but sometimes it can spawn before chinook. An attack helicopter will spawn and will only shoot at people that are armed with weapons; it will not shoot anyone that doesn't have weapons. This helicopter can also shoot rockets, incendiary blunts, and napalm. These only occurs when an attack helicopter is being shot down by online players. The reason why online players would shoot this helicopter is because it can drop military crates.
The cargo ship is a moving monument that you can board on the side of the ship using a ladder. This cargo ship spawns in every 2-4 days and goes around the whole map. But its not easy to take this moving cargo ship... It is guarded by scientists that use Sub machine guns, Rifles and Shotguns. The cargo ship can contain several locked crates up to 2! But this should not be done by players who do not have the proper gear.
Chinook is a military helicopter that will shoot at everybody when it spawns in. But its main goal is to drop a locked crate at a monument it chooses this crate can drop at water treatment, train yard, dome and a lot more but these are the most common ones.
Bradley is an APC in Rust that roams around a monument called Launch site. This APC fires at anybody that it comes across. You could also destroy this APC with 7 High Velocity Rockets. Once it has been destroyed it will drop 3 crates. But these crates will be on fire for 5 minutes so you must wait before you can open them.